1. Field of the Invention
The invention relates generally to audio enhancement systems, and more particularly, is directed to spatially enhancing audio for reproduction through a speaker.
2. Description of the Related Art
Many technology devices use a single small speaker to reproduce sound. Such devices include, but are not limited to, cellular telephones, personal digital assistants (PDA's), laptop computers, television sets, radios, and various small hand-held devices. Often such devices have poor audio capabilities and because only one speaker is utilized, they are monophonic. Thus, such systems often cannot accurately reproduce stereophonic information.
True stereophonic reproduction is characterized by at least two distinct qualities. The first quality is the directional separation of sound sources to produce the sensation of width. Directional separation is generally described as that which gives the listener the ability to judge the selective location of various sound sources, such as the position of instruments within an orchestra.
The second quality is the sensation of depth and presence that the directional separation creates. Presence is generally described as the feeling that the sounds seem to emerge, not from the reproducing loudspeakers themselves, but from positions in between and somewhat behind the loudspeakers. The term “ambience” is also used to describe this sensation of width, depth, and/or presence.
Attempts to reproduce stereophonic information with monophonic systems have included the approach of adding the stereophonic channels together with the intent of presenting information from all the channels through a single speaker. Unfortunately, merely adding the stereophonic information often results in the loss of information. For example, stereo information in one channel may be out of phase with information existing in another channel. When the two channels are added together, information is lost due to phase cancellation of the information.
Consequently the directional separation and the sensation of depth and presence are lost when different channels of stereophonic information are combined together using existing methods.